The invention relates to a liquid crystal display device having a layer of liquid crystal material between two substrates provided with electrodes and orienting layers, the orienting layers giving the liquid crystal molecules at the area of the substrates such a preferred direction that the liquid crystal material has a twist angle .phi.T across the thickness of the layer, the device being further provided with mutually substantially perpendicular polarizers at opposite sides of the layer of liquid crystal material.
Such a device can be used, for example, in LCD television, and also in datagraphic display devices.
A device of the above-mentioned type is described, for example, in DE-A 0,264,667. This application describes how smaller twist angles .phi.T, for example, between 10.degree. and 80.degree. are preferred for adjusting grey scales while larger twist angles (90.degree. or more) are more suitable for high multiplex ratios. At low values of d..DELTA.n (d: thickness of the layer of liquid crystal material, .DELTA.n: birefringence or optical anisotropy of the material) and suitably chosen states of polarization, such a device provides a good contrast and little discoloration.
A drawback, notably in the case of a twist angle of 90.degree. or more, is the fact that the contrast between crossed polarizers is angle-dependent around the normal to a front face of the display device and is considerably lower in one quadrant. Moreover, when changing the viewing angle, picture inversion occurs in the quadrant where the highest contrast is obtained due to the specific shape of the transmission/voltage characteristic in the associated viewing direction.